Apparatus for making standardized tape specimens

ABSTRACT

The apparatus employs a polished steel substrate on which a test tape with its adhesive side down is pressed by a rubber coated roller. The latter is moved over the tape in one direction and then in the reverse direction. The roller is connnected through a swinging yoke and a swivel joint to one end of a horizontally positioned actuator rod. The other end of the rod is provided with a slot which receives one end of a short rod which is adapted to rotate within the slot. The last mentioned rod, at its opposite end is fixedly secured to a small metal plate which is secured to an outer link of a chain passing over a number of aligned sprocket wheels. One of the wheels is driven by a gear to which power is transmitted through a gear train by a synchronous motor. The small plate, in following the moving chain link, causes the actuator rod to travel back and forth in strict alignment with its axis and at the same instantaneous speed. Thus, the roller is given a strictly uniform speed over the tape. The tape is dispensed from a large roll and cut to proper width by a pair of trapezoidal-shaped cutters, spaced 1 inch apart over which the tape is pulled from the roll.

United States Patent 72] Inventor Sylvester G. Domen, Sr.

3165 Orleans St., Mobile, Ala. 36606 [21] Appl. No. 789,056 [22] Filed Dec. 31, 1968 [45] Patented Sept. 21, 1971 [54] APPARATUS FOR MAKING STANDARDIZED TAPE SPECIMENS 5 Claims, 8 Drawing Figs.

[52] US. Cl 156/378, 156/580, 73/150 [51] Int. Cl G01n 19/04, B30n 3/02, G0lb 19/08 [50] Field oiSearch 156/378, 545, 582, 583, 580

[56] References Cited UNITED STATES PATENTS 3,322,604 5/1967 Schott, Jr. 156/583 3,436,963 4/1969 Domen, Sr 156/580 X Primary Examiner-Benjamin A. Borchelt Assistant ExaminerJerald J. Devitt Attorneys Harry A. Herbert, Jr. and Herbert H. Brown ABSTRACT: The apparatus employs a polished steel substrate on which a test tape with its adhesive side down is pressed by a rubber coated roller. The latter is moved over the tape in one direction and then in the reverse direction. The roller is connnected through a swinging yoke and a swivel joint to one end of a horizontally positioned actuator rod. The other end of the rod is provided with a slot which receives one end of a short rod which is adapted to rotate within the slot. The last mentioned rod, at its opposite end is fixedly secured to a small metal plate which is secured to an outer link of a chain passing over a number of aligned sprocket wheels. One of the wheels is driven by a gear to which power is transmitted through a gear train by a synchronous motor. The small plate, in following the moving chain link, causes the actuator rod to travel back and forth in strict alignment with its axis and at the same instantaneous speed. Thus, the roller is given a strictly uniform speed over the tape. The tape is dispensed from a large roll and cut to proper width by a pair of trapezoidalshaped cutters, spaced 1 inch apart over which the tape is pulled from the roll.

PATENTED $9 21 197:

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APPARATUS FOR MAKING STANDARDIZED TAPE SPECIMENS FIELD OF THE INVENTION Pressure sensitive tape is used for binding together various kinds of materials, carton cardboard, fiberboard, glass, etc. and forms a hermetic seal between the joined parts. The tapes may take many forms, such as plastic film, cellulose tape and paper and cloth tapes, depending upon the type of material which is to be bound and the durability of the joint required. But, whatever the type and use, it is essential that the tape adhere strongly to the foundation material over long periods of time, if necessary, regardless of whether the the tape requires moisture or merely pressure.

DESCRIPTION OF THE PRIOR ART The actual testing of the tapes have been set forth by standards promulgated by the American Society for Testing and Material (ASTM) in order that the same tape may be ordered from two or more competing manufacturers and the product received would be reasonably the same in quality. This would necessitate that each manufacturer has his own manufacturing and testing equipment. In addition, he should adhere to a standard and readily duplicatable way of preparing the specimen for test so that the results obtained from a standard test procedure can be accurately compared with the results obtained by a competing manufacturer on the same type of tape and using the same preparation and test procedure.

Notwithstanding the many kinds of material to which the tape is to be applied, also the different purposes and the various types of tape, it has been found by demonstration that in order to obtain consistent test results, it is desirable to form a specimen by applying the piece of tape under test to a polished stainless steel plate or substrate. The degree with which the tape adheres to the metal appears to bear a direct relation to the adhesive power as applied to other and perhaps many different materials. The overlying tape element, according to the standardized requirements of ASTM, should be cut to 1 inch width and not less than inches long, also must be pressed onto the substrate by a rubbercovered 4% lb. roller. The latter should be constructed so that the weight of the handle is not added to the weight of the roller.

Another requirement is that the specimen should be prepared within 2 minutes after the sample is pulled from the tape roll so as not to introduce any variable atmospheric effect on the adhesive. The tape after being cut to dimension is usually applied to the substrate by running the roller, first in one direction, and then in the other, by an operator who attempts to apply the same pressure to the successive specimens.

Some of the reasons which prevent strict conformity of the tape results are:

l. the pressure applied by the hand-operated roller is not strictly duplicated because this pressure would depend on the operator, when, in moving the roller through the forward and return strokes, he would unconsciously apply varying degrees of pressure at the handle of the roller;

2. the average speed with which the roller is moved across the tape in the two directions is not duplicated as between successive tapes of the same type, and;

3. the instantaneous speed is not constant throughout the entire travel of the roller even though the average speed may not have varied. Any one or all of these conditions have an ap preciable effect on the accuracy, and particularly on the certainty of duplication of the results.

SUMMARY OF THE INVENTION An object of the invention is to provide an improved apparatus for preparing specimens of tape which will not only satisfy the ASTM standards but will also assure complete uniformity in the manufacture of the specimen and will lend certainty of duplication during the test of the specimen. This object is attained in brief by connecting the rubber roller to a link of a motor-driven endless chain by means of a swiveled actuating rod and a special form of connector. The chain is driven by a synchronized speed motor which assures a con stant instantaneous speed of the chain and hence of the reciprocatory movement of the roller. The rod is maintained in a strictly horizontal direction throughout the forward and return movements of the roller. The connector is such that when the chain link is passing around the forward half of the front sprocket and the rear half of the rear sprocket, the actuating rod and hence the roller, will remain absolutely stationary. In this manner the limit of the roller travel is positively defined.

Another object is to provide an improved cutter for the tape which will give a more uniform and faster cut, keeping in mind the requirement of ASTM as to the maximum time allowed for pulling the tape from the roll and allowing for the different types of tape.

Other objects and features will be apparent as the specification is perused in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 represents an elevational view of the improved structure pressing a tape sample onto a substrate in preparing a test specimen.

FIG. 2 shows a plan view of the structure.

FIGS. 3, 4 and 5 are fragmentary action views, showing the different positions assumed by the link to which the connecting rod is attached and as the link successively passes around the end sprocket wheels.

FIG. 6 depicts a fragmentary view, in perspective, of the tape dispenser and the improved tape cutting device.

FIG. 7 represents a detail, showing in perspective, the manner in which the roller can be moved out of the way to rest on a support when the machine is not being used.

FIG. 8 shows in perspective, a fragmentary view of one of the many testing devices to which the test specimen can be subjected.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. I reference character I designates an in verted U-shaped base, constituted preferably of steel. The top and side portions of the base are sufficiently thick as to be rigid and thus maintain the operating parts mounted thereon in strict alignment. There is a plate 2 of sheet steel secured as at 3 to a strap 4 at each end, the strap being positioned on the underside of the base. The plate 2 has longitudinal and transverse markings 5 located at equal distances apart which serve to facilitate the positioning of members which are placed thereon. There is also a locating pin 6 projecting upwardly from the base and through the plate 2, this pin extending through an opening in a substrate 7 on which the tape sample 8 (FIG. 2) is to be rolled with its adhesive treated side down. The substrate is preferably constituted of polished steel and the latter, together with the short length of tape, is termed hereinafter as the specimen.

A roller generally designated as 9 and weighing approximately 4% pounds is employed to press the tape against the substrate, after which the tape and plate are removed at the pin to subject the specimen to the quality and comparative tests. These tests do not form part of the invention and it is sufficient to state that they may include the holding power test, the peel test, the creep test, the slippage and perhaps other tests. The presence of the metal substrate facilitates the testing processes and adds to the uniformity of the results.

The roller 9 comprises a solid metal core 10 covered with rubber about Va inch thick, having a durometer hardness of to 80. The cylindrical surface of the roller represents a true surface, void of any concave or convex deviation, so that the roller will apply uniform pressure across the width of its entire surface. There are roller bearings (not shown) in the core 10 carrying the ends of a yoke 11. The latter may be secured to the bearings by cotter pins 12. The yoke terminates at the other end in a pair of short parallel extensions 13 spaced apart to receive the tongue 14 of a horizontally extending actuator rod 15. A cotter pin 16 extends through the extensions 13 and the tongue 14 so as to form a swivel joint. The rod 15 is slidably mounted in a vertical upright member 17 secured as by bolts (not shown) to the base 1. As shown in FIG. 7, the distance between the upright 17 and the pin 16, as well as the height of the upright, are such that the roller 9, when it rests, can be swung upwardly about the pin 16 to cause the roller to set lightly on top of the upright. In this manner, the true surface of the roller is maintained over a longer period of time than if it were allowed to set on the plate 2 during the rest periods. The rod 15 passes through the upright 17 and terminates in a flattened end 18. This end portion is given a reciprocatory motion by a chain mechanism which will now be described.

There is a wall member 19 extending upwardly from the base and forming the leg of an angle iron member 20 which is screwed, as at 21, to the base. This member is extremely rigid since it serves as a support for the chain mechanism including a number of gears and the driving motor. The front end of the wall may be curved as indicated at 22 (FIG. 1) while the other end is cut square. The wall is provided with four openings 23, 24, 25 and 26 for receiving stub shafts which carry sprocket wheels 27, 28, 29 and 30, respectively. These sprockets are of the same size and are arranged edgewise in line with one another. The sprockets 27, 28 and 29 can freely rotate on their shafts but the sprocket 35) is secured to its shaft by a key 31. The shaft 26 extends through the wall 19 and has fixedly mounted thereon a large gear 32. The shaft passing through the opening 26 preferably is mounted on ball bearings on account of carrying the relatively heavy gear 32.

The wall 19 is provided with an opening through which a shaft 33 extends for mounting a small gear 34 which meshes with the large gear 32. The same shaft 33 also carries a gear 35 and these two gears may be fixed together. There is a motor 36 for driving the apparatus, this motor preferably being of the alternating current type and therefore running at a strictly constant speed. The motor is secured in any suitable manner to the base 1 and its end abuts the wall 19. The motor may be controlled by an on and off snap switch 36 connected to a source of alternating current (not shown) preferably of 60 cycles I 10 volts. A fuse 36 may also be employed in the circuit for protective purposes.

A motor shaft 36 passes through the wall and carries a bushing 38. The shaft is provided with a gear 39 which meshes with the gear 35. Consequently, when the motor is energized by snapping the switch to the on position the gear 39 will power drive the gear 35 and the attached gear 34, also the large gear 32 to which the sprocket wheel is attached. There is an endless chain 40 extending over and under each of the sprockets 27, 28, 29 and 30 with a well-known provision (not shown) for tightening the chain.

As shown more clearly in FIG. I, a small plate 41 is secured at one end, as by welding, to an outer link 42 of the chain and this plate carries a short connecting rod or shaft (FIG. 2) which slidably extends through an opening (not shown) in the flattened portion 18 of the actuator rod. Consequently, when the motor 36 is energized to actuate the train of gears and cause the sprocket wheel 30 to rotate, for example, in the counterclockwise direction as seen in FIG. 1, the upper length of the chain moves from right to left and the lower length moves from left to right. Thus, the link 42 to which the plate 41 (FIG. 1) is attached, is carried by the chain from left to right until the center of the rod 43 coincides with the vertical center of the sprocket 30 as seen in FIG. 3, and as the link moves upwardly around the right-hand end of the sprocket the actuating rod will remain stationary because the plate 41 and its rod 43 will be caused to rotate within the opening in the flattened portion of the actuator rod 15. The latter will maintain its stationary position until the plate 41 will have moved 180 from the position shown in FIG. 3 in which case the link 42, in moving with the chain will have caused the actuator rod to move to the left, still in its horizontal position. in so doing, the rod will have caused the roller 9 to move likewise to the left and thus roll down the tape sample 8 onto the substrate 7. This operation of plate 41, in maintaining a stationary position of the actuator rod 15 while the chain is moving around the sprocket 30, is shown by the successive positions of the plate 41 in FIGS. 3,4and 5.

It is apparent that the plate 41 and its rod will likewise rotate within the end opening in the rod 15 at the left-hand end of the chain so that the actuating rod 15 in effect moves endwise through a longitudinal distance, going forward in one direction and then in the backward direction as represented by the distance between the centers of the sprockets 27 and 30. Assuming that the motor 34 is of the synchronous alternating current type so that the speed is strictly constant, the roller 9 will be caused to roll over the tape sample first in one direction and then in the other direction at precisely the same instantaneous speed. Moreover, in order that the pressure asserted by the roller will be strictly constant, the actuating rod 14 will always assume a horizontal position through its entire travel, so that notwithstanding the presence of the swivel joint at 13, there is not the slightest upward or downward move ment of the yoke 11 since this member is always maintained in alignment with the actuating rod 15 and the latter is slidably held within the opening in the upright 17. The length of the chain is so supported by the sprocket wheels as to have not the slightest sagging effect so that the rod 43 cannot be diverted from its rectilinear line of movement. The operator, therefore, has no control over the pressure exerted by the roller 9 nor of the speed with which the roller is moved over the tape sample so that any possible variation in pressure or speed of the roller is completely eliminated by the use of the endless chain. Thus, the successive pieces of tape are necessarily given the same adhering contact with the substrate throughout its length.

In order to run certain of the tests referred to hereinbefore,

it is desirable that a small length of the tape be prevented from adhering to the substrate notwithstanding the passage thereof of the roller. It may be desirable to apply a strip of onion paper having a waxy surface and of a width depending on the length of tape that is to remain free from adhesion, the strip being placed between the tape and the substrate. The adhesive on the tape does not normally adhere to this surface so that the paper can be readily removed when the specimen constituted of the combined tape and substrate are removed from the pressing apparatus. One typical example of a test will be described showing the desirability of preventing the holding power of the adhesive from taking effect over a portion of the tape.

The roll of tape which is to be evaluated as to the quality of material, and holding power of the adhesive, etc., is shown generally at 44 (FIG. 6). The roll may be of the regular size and ordinary material, carrying an adhesive on one side and mounted on a stiff cardboard core 45 which fits tightly over a metal drum 45', of a standard inside diameter. The rolls come in various widths and it will be assumed that the roll illustrated is about 2 inches wide which is the popular size. The steel drum 45' is carried by a shaft 46 is rotatable on bearings and provided in a pair of metal uprights 47. These uprights, one on each side of the roll is bolted or welded to the base I. The shaft 46 is preferably fitted at each end in a slot cut diagonally in the uprights 47 in order to receive both ends of the shaft without permitting the latter to move upwardly when a pulling effect is exerted on the free end 48 of the roll. Thus, the roll 44 of adhesive tape can readily turn on these bearings of the drum.

It has been pointed out that in accordance with the requirements of ASTM, it is essential that the tape after being pulled from the roll 48 should be cut to 1 inch wide regardless of the roll width, and provide a sample of not less than 5 inches long. A time limit of two minutes is set during which time the tape must be accurately cut and pressed onto the substrate 7 to form the complete specimen and immediately thereafter limit is that the air must not be allowed to come into contact with the adhesive for any extended period of time. The test strip of 1 inch wide can not vary in the slightest throughout its width and must have parallel clean cut edges. This requirement is necessary to insure exact uniformity between the specimens.

In order to achieve the structural requirements of ASTM, I provide in close proximity to the roll 44, an improved cutting device, generally indicated at 49 which performs the function of providing a strip of exactly the requisite width. The device, as shown in FIG. 6, is formed of two flat members 50 of hardened refractory metal, cut to a trapezoidal shape and separated from one another at the top by a pair of corrugated rollers 51 journaled in the members 50. The lower ends of the latter are spaced apart by a block of metal (not shown), a bolt 52 passing through the flat metal members and the metal block. There is a pair of ears 53 extending outwardly from the spacing block and these ears together with the block furnish a support for a rigid arm member 54 of metal having a horizontal portion which is attached to the block and a vertical portion 55 which extends loosely in an opening 56 formed in an upright block member 57. The member is provided with outwardly extending wings 58 and the latter are screwed as at 59 to the upper surface of the base 1. Due to the thinness of this base it may be desirable to provide nuts for the screws at the under side of the base and, if desired, a strengthening strap. There is an opening in the upright 47 about half way up and, in the middle of the block, this opening being tapped to accommodate a screw 60 which can pass therethrough and contact the surface of the vertical portion 55 of the arm. For ease in turning the screw, a header 61 may be secured to the screw and provided with an opening for receiving a short rod to facilitate the turning of the screw. Thus, bar portion 55 and the cutter can be adjusted as to height within the opening of the upright 57.

The trapezoidal members 50 are bevelled along their upper edge to constitute cutting surfaces, leaving two sharp points at 61', which are spaced, preferably 1 inch apart, depending on the width of the tape to be used in the specimen. The cutting points 61' are located a short distance away from the roll of tape and slightly above the axis of the shaft 46. Thus, as the tape is pulled from the roll and simultaneously pressed downwardly against the sharp points, a strip 8 of tape of exactly the requisite width is obtained, as shown in FIG. 6. A length of tape of about 5" or 6" long is pulled from the roll and a pair of scissors quickly severs the sample from the roll.

The cut sample is then laid, adhesive face down, on the substrate 7 together with the use of a short strip of onion paper at the position where the effect of the adhesion to the substrate is to be avoided. The roller 9 is then brought down from its perch on top of the upright 16 and it is laid on the substrate that is not occupied by the tape whereupon the motor is started by snapping the switch 36 (FIG. I). The roller will then be caused to make one excursion over the length of the tape forward and back without the slightest change in the downward pressure at the roller. Moreover, the 4% lb. roller is moved at a strictly constant instantaneous speed in both directions on account of the continuous movement of the chain as explained hereinbefore. The ideal speed for the roller should preferably be at the rate of 12 inches per minute according to the ASTM standard and this speed can be determined by the teeth ratio of the gears 39, 35, 34 and 32, taking the speed of the motor into account and the size of the sprocket wheel 30. The specimen formed of the substrate and applied tape is then ready for testing, and the test portion of the specimen is subjected to any or all of the tests which one will be mentioned hereinafter and having been prescribed by ASTM.

The presence of the width cutting device 49 and its proximity to the tape roll 44 enables a sample strip of proper width and smooth parallel sides to be applied to the metal substrate in the minimum time. Due to the angle with which the flat plates 50 and the sharpened pointlike edges are pressed against the tape sample 8 as the latter is drawn from the roll 44, the sample is out clean, i.e., without any chopping or sawing effect, and this again decreases the probability of failure to reproduce the exact conditions under which successive pieces of tape can be applied to the substrate.

EXEMPLARY TEST OF SPECIMEN.

There are many different types of tests to which a combined tape and substrate can be subjected, and in all of which the preparation of the specimen must be standardized and carefully made. In case of the holding power test which is illustrated in FIG. 8, perhaps one of the more important for a given tape, a 5 inches or 6 inches length of the tape is cut exactly 1 inch wide by cutting points 61'. In this test it is necessary that only a portion 1 inch long be caused to adhere to the substrate, so that the adhering portion represents 1 square inch. The remainder of the strip is prevented from adhering as explained hereinbefore. The adhering portion should occur at one end of the strip leaving the remainder of the strip free. The substrate 7 is then secured to the top frame 62 (FIG. 8) of a cabinet in such a way that the free end 63, that is, the portion of the tape which is disengaged from the substrate is permitted to angle downwardly as shown in the figure. The lower end of the tape may be reinforced by a cross strip 64 and a hole 65 is pierced through the tape and the cross strip. A weight 66 of a standard, together with a hook 67 is attached to the hole. There may be many competing tapes tested simultaneously within the cabinet from each of which a similar weight is hung. Marking strips 68 may be attached to the individual sample tapes while being tested, to give a visual indication of the gradual separation of the tape from the limited area on the substrate at the point marked 69 under the influence of the weight 66. The front of the cabinet is preferably covered by a plastic curtain (not shown) so that the interior can be maintained uniformly at a predetermined standardized temperature. Obviously, the slower the tape separates from the substrate as shown by the successive positions of the marker 68 will become at least one comparable measure of the holding power of the tape under test. Other tests such as the creep test, adhesion test, slippage, and still others, may employ different apparatus from that shown. 'Some of the tests require adhesion of the tape over the entire five inches of the specimen rather than a limited area of the adhering portion. But in all cases, the success of the test from the comparable values obtained, depend almost entirely on the uniformity with which the sample piece has been cut to size, the manner in which it has been pressed against the substrate which includes the feature of the present invention, namely, moving the roller over the tape both ways at the same instantaneous speed brought about by the chain mechanism and the connection between a link of that chain and the rod which keeps the actuating rod for the roller in a strictly horizontal position throughout the travel.

Iclaim:

1. Apparatus for preparing uniform adhesive tape specimens for test purposes, said apparatus comprising: a base member adapted to receive a metal substrate on which is placed a test sample of the tape with the adhesive side down, and means for applying pressure to the tape, said means including a roller having a centrally located bearing, an actuator rod swivelly mounted with respect to said bearing and located in a horizontal position, and means including a link chain mounted on sprockets and operated by a motor, and a connection between one of the links of the chain and said rod for moving said rod endwise, back and forth at the same instantaneous speed throughout its longitudinal travel while main taining the rod in the horizontal position whereby the roller is caused to move over the tape at the same instantaneous speed in order to provide a tape specimen of high reproducible quality.

2. Apparatus for preparing uniform adhesive tape specimens according to claim 1 and in which said connection includes a flattened end portion of the actuator rod having an opening therein for slidably receiving one end of a connector rod, the other end of the last-mentioned rod being secured to a plate which is connected to a link of the chain.

3. Apparatus for preparing adhesive tape specimens according to claim 1 in which said connection includes a plate swivelly mounted at one end with respect to the actuator rod and the other end of which is fixedly secured to a link of said chain.

4. Apparatus for preparing adhesive tape specimens according to claim 1 and in which one end of the actuator rod is swivelly connected to a yoke which supports the roiler and the other end is swivelly connected to said plate which is fixedly secured to said chain link.

5. Apparatus for preparing adhesive tape specimens according to claim 1 and means for moving the actuator rod in a direction coincident with the axis of the rod solely between the limits represented by the vertical lines drawn through the center of each of the first and last sprocket on which the link chain is mounted. 

2. Apparatus for preparing uniform adhesive tape specimens according to claim 1 and in which said connection includes a flattened end portion of the actuator rod having an opening therein for slidably receiving one end of a connector rod, the other end of the last-mentioned rod being secured to a plate which is connected to a link of the chain.
 3. Apparatus for preparing adhesive tape specimens according to claim 1 in which said connection includes a plate swivelly mounted at one end with respect to the actuator rod and the other end of which is fixedly secured to a link of said chain.
 4. Apparatus for preparing adhesive tape specimens according to claim 1 and in which one end of the actuator rod is swivelly connected to a yoke which supports the roller and the other end is swivelly connected to said plate which is fixedly secured to said chain link.
 5. Apparatus for preparing adhesive tape specimens according to claim 1 and means for moving the actuator rod in a direction coincident with the axis of the rod solely between the limits represented by the vertical lines drawn through the center of each of the first and last sprocket on which the Link chain is mounted. 